Temperature-indicator for transformers and the like



V. Nh MONTSINGER.

TEMPERATURE {NDICATOR FOR TRANSFORMERS AND THE LIKE.

MPLCATlON FILED MAYZY. 1918.

atented Mar. l5, 192] when UNITED- STATES PATENT oFFica,

VINCENT M. MONTSINGER,'GF 'PIT'TSFEELD MASSACHUSETTS, ASSIGNOR T0 GENERAL ELECTRIC COMEAN'Y, A CORPORATION 0F NEW YORK. f

TEMPERATURE-INDICATOR FR TRANSFRMERS AND THE LIKE.

Specification of Letters Patent.

Application filed May 27, 1918. Serial` No. 236,961.

To aiZZ idiom t may concern.

Be it known that l, VINCENT M. MONT- siXor-vn, -a-citizen of; the United States, residing at jittselchin the vcounty o'Berl shire, ,State of lilassacliusetts, have invented. certain new and useful improvements in Temperature-lndicators for Transformers and the like, of 'which the following is a speciiication.

invention relates to a temperature indicator for transformers and the like, and it has for its object the improvement of a device oi? this character.

lt is Well known that transformers, and other similar apparatus, deveiop heat during their operation, and that there will be a point Within the transformer or other deyice known as the hot spot Where the temperature is higher than at any other point, and since the temperature of no .part of the transformer may safely exceed. a certain predetermined value. the capacity of 'the trans.

former is limited by the temperature attained by this hotspot. 'A This spot, hon'- ever, is usually located Within the windings and its temperature therefore, cannot be determined by the use of the ordinary thermometer, and the temperature of the enterior parts of the apparatus or of the oil the apparatus is immersed in oil' s no certain or accurate indication of afford A. the temperature of `the hot speri in order, therefore, to operate a transformer with safety, it is usually necessary to lkeep the temperature of the het spot as determined by theoperator considerably beiow the permissible' hot spot temperature; otherwise, the actualy hot spot temperature is likely to pass the permissible temperature with consequent injury to the transformer.

'ln accordance Withmy invention the temperature of the interior of lthe windings is determined by one or more resistance Windings wound together with, and inductively related to the main windings of the transformer or other apparatus and disposed in the portion corresponding to the hot spot and an indicator is provided which responds to variations in the temperature and resistance oi the resistance Winding.

For a better understanding of my invention reference may be had to the accompanying drawing in Which Figure 1 is a diagrammatic View illustrating my invention used in connection with a transformer; and Fig.

l. by the conductors is a diagrammatic View further illustrating certain parts or' the circuits.

referring now to the drawings and first to Fig. l., 10 is the core of a'transformer, or other like apparatus, on which is disposeda primary winding l1 connected to supply conductors 12 and 13 and a secondary Winding 14- connected to a load circuit represented 15 and 16. resistance .winding 17, more clearly shown in Fie. 2,

v,having alsubstantial temperature coeiicient (either positive or negative, but in this application assumed to be positive) is connectu ed at one end to suitable point on the main Winding 11, and being Wound with the main Winding is in inductive relation therewith, and is in such close thermal relation to the main Winding that it assumes substantially the same temperature as .the main Winding. This resistance member preferably has a less i number of turns, for example, one less turn, than' a selected portion 19 (see Fig. 2) of the main winding 11 or" the transformer. In the preferred form oi my invention, a second resistance member 18, which is 'formed of a material having zero temperaturev coeiicient, is also disposed between the main windings and has a greater-number of turns, for: example, one more turn than the main winding 19. This resistance member is also connected to the main winding 11 and its free end is connected by aconduc'ror 21 to the free end of the resistance' winding 17. A third resistance member 2O is also Wound between the main windings and is-connected through the primary Winding 22 Vof an insu.- lating transformer 26. to the conductor 21 between the terminals ofthe resistance members 17 and 18. windings 17 and 18 form two legs of a `Wheatstone bridge, the primary winding 22 and the Winding 2O being connected in series across equipotential points of the bridge at some chosen temperature which is the temperature at which the resistance of 17 and 18 are equal. rifhe insulating current transformer Q6 which is interposed between the windings of the transformer and the indicating instrument, eifectually insulates the latter' from the transformer and makes the instrument safe tor the operator.

The secondary Winding of the insulating transformer 'is connected to tbe current coil 28 of the instrument Q9, which is in ciiect, a

Patented Mar. 15, 192i..

It is apparent that the I 2 wattmeter.- A voltage coil 30 is alsopro- 110 l through die Same and is connected 5;@ 'the supp y wnductm-s l2 and L mr kugh lle voltage 'mms- Snow?? El number of turns than does the winding l?, a hlghr '-Jotage will ne mduced u the winding 18 dum in the Winding i? and th `re w be a difference of patent-iai bei?? en the pons 3l and 32 which are located ai the Qnds of the yessmse .membels Y' m 18, respectively and cmren will Qcuat cru which incl fes che Wnf ings 17-13 and he conduct@ EL Sinne the "nd'ngs l? and l8 :me So closely intaxQaf'Led h@ crcu'l W. be non-inductive and the circulating ciment Wil be mted Gilly by the resstances of l? and i8. The windig's are so arranged tha at the, Dftamzwl terry pe aturef the transmmer, say ai 1GO d@ grees the voages S the pens 23 and,

Q4 will be "the same, windings may(- ready be so afgang-M1, smc@ h@ ncmg resstzmceo ih@ winding; TLS c LS ge with-'the consequence that he Voltage of the bint 2 will be raised elave'v ao the point 23 and a cufen'. caused to Cuculate through the pimay winding 22, thaw by setting up a Guten' in h@ Cuman coil 2S 'sf h@ wattmetey, und the hand of the nsgrument will tuzn Ao "dw light nasmuch as hedtem-ferature change is u, {im-2- on of h@ lesstance of ih@ .member die va'nmezer .may be cabra-ed in deglees. Since hesf@ is no cui-feat in h@ primary Wndmg at *im nofmn wo'rkg empemf ture, Say 10() (legi-ees (L and snce 'this Caibmton shoud be on the pon of Zero o'que @f me scale the hand the uslument W normal@ point to im nemediaa pmt ik? Scale. Un an ncreas in empemue, me hzm 'J'l be moved '11o the :cigni fn a.' smumd yne of n'srument) i and su fecmase m tempam'e, das hand' im@ bv sa? 315mm@ .18,

pemu 4;.. me

i@ be "limited file (ehown and 35h@ anpended which 00m@ of my having' :a

wound mgchez Wi lnductive vakman Sponsvfs is 3. n coma' comprising a mm 'having two of its am relaon to Suid Tumi "Lure coe ndicang fh@ changes 1 said arms when the temp vim mg, a

il@ hm@ herein shown suneform, 01": my im* 

